<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title> 层级选择器。父子关系 </title>
    <style>
        .box p{
            color: red;
        }

        .box > p{
            font-size: 80px;
        }
    </style>
</head>
<body>
    <div class="box">
        <p>一级子元素</p>
        <p>又是一个子元素</p>
        <div>
            <p>二级子元素</p>
            <div>
                <p>三级选择器</p>
            </div>
        </div>
    </div>
</body>
</html>